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Delve deeper into hot topics featured in NGM's June Geographica and Who Knew? with help from Resources. Click on a link, pick up a periodical, browse through a book, and explore!
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We Got the Blues
Humanity's obsession with a certain color

When we finally get around to writing the entire story of civilization, we'll devote a chapter to the color blue. Sure, children around the world choose red as their favorite color. But that's just a phase, like tearing the crust off bread. Make no mistake: Blue rules.

For thousands of years humans have found ingenious ways to turn things blue. In the ancient Mediterranean, biblical blue dye came from a hermaphroditic snail with a gland that generates a fluid that becomes blue when exposed to air and light—at least when the mollusk is feeling masculine. "They had to extract the glands when the snails were more male than female," explains Tony Travis, a historian and chemist at Jerusalem's Hebrew University.

Another blue dye came from a plant called woad. Its leaves had to be ground and fermented before the pigment emerged. Celts painted their bodies with it (think Mel Gibson in Braveheart). Medieval scribes illustrated manuscripts with it.

The blue in woad came from a molecule scientists refer to as indigo. But woad wasn't the best source of blue. Another plant—also known as indigo—produced the color more effectively. Indigo plantations sprawled across Asia, while woad lost luster.

Eventually synthetic dyes replaced natural ones. In 1897 the Germans manufactured the first synthetic indigo from coal-tar derivatives. Synthetic dyes triggered an explosion of blue fashions in the 20th century. Policemen switched from black uniforms to blue. The blue blazer replaced the black suit. And in the 1950s blue jeans took off, radiating youth and rebellion.

Next up: biotech blue. When Australian toxicologist Elizabeth Gillam was studying bacteria implanted with human DNA, her cultures unexpectedly turned blue. She suspected a mold contamination. But after conferring with Fred Guengerich, a colleague at Vanderbilt University, Gillam realized she'd stumbled onto something wonderful: The bacteria were producing the indigo molecule as part of their metabolism. "This is a good lesson for student scientists," says Gillam. "If something looks bizarre, don't discount it. It might be much more interesting than the result you expected."

Biotech indigo could be used to create blue plant tissues, including flower petals (imagine a perfectly blue rose). Scientists speculate that the process might even yield blue cotton, which would mean your jeans wouldn't need any dye. But then how would we ever get that nice faded look?

—Joel Achenbach
Washington Post staff writer

Web Links

Adolf von Baeyer
Nobel laureate Adolf von Baeyer received the award for chemistry in part for his work in developing synthetic indigo. This website links to a biography of von Baeyer.

Color-Blind Tests
There are several websites available that post tests for color blindness. This popular site has tests and more information on the condition.

Commercial Color
You might be familiar with Pantone colors if you deal with design for a living. The company's website has several interesting articles about various colors and how humans react to them. Peruse the articles in the "All About Color" section.

More Articles By Joel Achenbach

Military Theory and the Force of Ideas
As military technology becomes more and more advanced, there is less room for valor on the battlefield.

Rough Draft
Writer Joel Achenbach's column is gaining a cult following. It takes a sometimes humorous, sometimes eye-squinting, but always intelligent look at today's headlines, personal interests, and the little life-annoyances we all live with.

Free World Map

Ball, Philip. Bright Earth: Art and the Invention of Color. Farrar, Straus, and Giroux, 2001.

Farrant, Penelope A. Color in Nature: A Visual and Scientific Exploration. Blandford, 1999.

Pastoureau, Michel. Blue: The History of a Color. Princeton University Press, 2001.


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